Notable Impact of Paleotectonic Stress on Gold Mineralisation in the West Qinling Orogen

ABSTRACT The Zaozigou gold deposit, located in the Xiahe‐Hezuo region, is a large‐scale gold‐polymetallic deposit in the West Qinling metallogenic belt. Its mineralisation exhibits a close genetic association with fault structures. Data on veins and fault slip offers critical evidence for reconstructing the complex deformation history during the metallogenic phase. It was by adopting fuzzy clustering and multiple inverse methods for stress inversion of these data that changes in the metallogenic geological environment and paleotectonic stress field were effectively clarified. Based on the analysis of the stress inversion results, two distinct stages of paleotectonic stress states have been identified: the initial metallogenic stage was dominated by a NW–SE trending extensional stress field, while the subsequent stage was controlled by a NE–SW trending compressional stress field. The initial stage may be related to the northward subduction of both the South China Plate and the Merlue Basin, which acted as the primary dynamic force driving extensive magmatic activity in this region. This tectonic–magmatic process primarily exerted a controlling influence on the formation and development of veins with S‐N–NE orientations, as well as a limited number of NW‐trending veins, within the mining district. The transition to the NE–SW compressional stress field during the subsequent stage was triggered by the continental collision event that occurred following the complete subduction of the Mianlue Basin. This significant tectonic transition not only accelerated the reactivation and deformation of pre‐existing faults and veins but also facilitated the generation of near‐E‐W‐striking structural systems, which provided favourable ore‐hosting spaces for the second phase of mineralisation. This study establishes a close genetic correlation between specific tectonic evolutionary events and metallogenic pulses in the Zaozigou gold deposit, and further emphasises the scientific significance of paleotectonic stress field reconstruction for deciphering the spatiotemporal evolution of tectonically controlled metallogenic systems in complex orogenic belts. Furthermore, the technical approach and research framework adopted in this study provide a valuable reference for investigating and interpreting the poorly constrained paleostress evolutionary histories of other metallogenic districts within similar tectonic settings.